Capture method — Gill or fixed net
Capture area — Pacific, North West (FAO 61) and Central (FAO 71,77)
Stock area — Western and Central Pacific
Stock detail — All Areas
Updated: December 2019
The yellowfin tuna fishery in the Western and Central Pacific Ocean (WCPO) is the second largest after skipjack, and is assessed and managed by the Western and Central Pacific Fisheries Commission (WCPFC). The latest stock assessment was carried out in 2017 using data up to the end of 2015 and shows that overfishing is not occurring and the stock is not in an overfished state. Maximum Sustainable Yield (MSY) is 670,800t. The next stock assessment is due in 2020. Catch in 2018 was 666,971t - the second highest on record. The scientific committee continues to recommend measures to reduce fishing mortality on juveniles and maintain current spawning biomass levels. There is no TAC or harvest control rule established. As of January 2018, a bridging measure is in force to manage bigeye, yellowfin and skipjack - all caught together. As part of this, spawning biomass for yellowfin is to be maintained at recent levels (33% of unfished levels). The bridging measure includes a number of new measures and consolidates some pre-existing ones and includes limits on vessel days and 5 months of closures for purse seine sets on Fish Aggregation Devices (FADs). An evaluation of this measure in 2019 found that the measure will marginally fail its aims for yellowfin as SB is projected to experience a small decrease. Data collection mechanisms are not in place to assess whether countries are complying with the legislation. Observer coverage on purse seiners is poor in areas not specified in the bridging measure.
Approximately 19% of the WCPO yellowfin catch is taken in various, more subsistence style netting operations such as ring and gill nets. Gillnets used for catching tuna and tuna like species can be 7 km and are known for extremely high bycatch including endangered marine turtles, whales, dolphins and sharks. WCPFC bans the use of gillnets over 2.5km long, but monitoring is poor and a default red rating has been applied.
Tuna belong to the family Scombridae. They are large, oceanic fish and are seasonally migratory, some making trans-oceanic journeys. Yellowfin are found throughout the world’s tropical and subtropical seas, except the Mediterranean. They often form large, size specific schools, frequently associated with dolphins or floating objects. Yellowfin is a large fast growing species, reaching maximum sizes of 240cm in length, 200kg in weight and an age of 8 years. They mature when 2 to 5 years old and mainly spawn in summer. Smaller fish are mainly limited to surface waters, while larger fish are found in surface and deeper waters, but rarely below 250m. Yellowfin has medium resilience to fishing.
Western and Central Pacific
The yellowfin tuna fishery in the Western and Central Pacific Ocean (WCPO) is the second largest after skipjack, and is assessed and managed by the Western and Central Pacific Fisheries Commission (WCPFC).
A stock assessment was last carried out in 2017 using data up to the end of 2015. There is a 96% probability that overfishing is not occurring (F at 0.74Fmsy) and a 92% probability that the stock is not in an overfished state (spawning biomass levels (SB) 33% of unfished levels and median spawning biomass levels, SB, at 1.39SBMSY). Maximum Sustainable Yield (MSY) was revised upwards from 586,400t in 2014 to 670,800t in the new assessment. Total yellowfin catch in the WCPO has slowly increased over time but jumped to a new level in 1998, with annual catches regularly exceeding 500,000t ever since. Catch in 2018 was 666,971t - the second highest on record. This was a 2% decrease from 2017 and a 9% increase from the 2013-2017 average. The next stock assessment is due in 2020.
The stock has been continuously declining for about 50 years, since the late 1960’s. Levels of fishing mortality and depletion differ between regions, and fishery impact is highest in the tropical region, mainly due to the purse seine fisheries in the equatorial Pacific and the “other” fisheries within the Western Pacific. Both juvenile and adult fishing mortality show a steady increase since the 1970s, but while juvenile fishing mortality has stabilized since the late 1990s, adult fishing mortality has increased continuously. The scientific committee continues to recommend measures to reduce fishing mortality on juveniles and maintain current spawning biomass levels.
Most tuna stocks range across and are accessed by numerous coastal states, making harmonised and effective management of these individual stocks very difficult. As a result, intergovernmental Regional Fisheries Management Organisations (RFMOs) have been established. There are five main tuna RFMOs worldwide and it is their responsibility to carry out data collection, scientific monitoring and management of these fisheries. The tuna fisheries in the Western and Central Pacific Ocean (WCPO) are managed by the Western and Central Pacific Fisheries Commission (WCPFC). Whilst the RFMOs are responsible for the development of management and conservation measures, the degree to which they are implemented, monitored and enforced still varies significantly between coastal states. For this reason, it is important to choose tuna that has been caught by vessels that are well regulated by their flag state.
WCPFC has put in place a lower limit for the spawning biomass of bigeye, skipjack, and yellowfin tuna of 20 percent of unfished levels (SB/SBF=0, aka spawning biomass depletion ratio), below which the stock should not fall. For skipjack there is also an interim target of 50 percent of unfished levels, which was adopted in 2015 and has been reached. The scientific committee recommends reducing fishing mortality on juvenile bigeye and yellowfin in the tropics, through preventing increases in overall fishing mortality, until targets for these two stocks can be agreed. The commission is looking to establish harvest strategies for key fisheries and stocks but has not yet completed this work and so, as of January 2018, a bridging measure is in force to manage bigeye, yellowfin and skipjack - the measure lasts until harvest strategies are in place or until February 2021. As part of this, spawning biomass depletion ratios for bigeye and yellowfin are to be maintained at recent levels (the average from 2012-2015) and skipjack at 50 percent. The bridging measure includes a number of new measures and consolidates some pre-existing ones, and is outlined below.
In the tropical region, between 20 degrees North and 20 degrees South, the following applies:
The use and deployment of FADs is prohibited for 5 months of the year (3 months for Kiribati and the Philippines). VMS polling frequency increases to every 30 minutes during the FAD closure.
Effort limits (in vessel days) apply to purse seining on the high seas (excluding Small Island Developing States, SIDS): limits vary by country. In order not to undermine the effectiveness of this, countries cannot transfer effort into areas outside of this region.
To create an incentive to reduce the non-intentional capture of juvenile fish, to discourage waste and to encourage an efficient utilization of fishery resources, purse seiners must retain on board and then land or transship at port all bigeye, skipjack, and yellowfin tuna (also applies to national waters).
All purse seine vessels operating on the high seas or within national waters in this region must carry an observer. This also applies to purse seiners anywhere in the convention area fishing in waters under multiple countries’ jurisdiction or moving between the high seas and national waters.
The number and capacity of large (over 24m) purse seiners and longliners (with freezing capacity and ice-chilled) operating in this area is frozen to 2016 levels (excluding SIDs and Indonesia).
An evaluation of this measure in 2019 found that it would achieve its targets if bigeye recruitment remains high, but if it declines, fishing mortality will double to above FMSY and biomass has a 20% chance of dropping below the limit reference point. For yellowfin, the measure will marginally fail its aims as SB will experience a small decrease. However, data is not in place to assess whether countries are complying with the legislation.
Other measures that apply to the wider convention area:
The number of drifting FADs with activated instrumented buoys deployed at any one time is limited to 350 per purse seine vessel.
Catch and/or effort limits apply for purse seining within national waters (both the type of limit and the amount vary by country).
There are country-specific limits on longline bigeye catch, and by 2020 hard limits for bigeye and a framework to allocate them amongst countries shall be developed.
Catches by other commercial tuna fisheries for bigeye, yellowfin or skipjack tuna (excluding those taking less than 2,000 tonnes) shall not exceed either the average level for the period 2001-2004 or the level of 2004.
There is a requirement to submit FAD management plans, including information on strategies used to implement closures and other measures for reducing mortality of juvenile bigeye. A number of aspects in the bridging measure have been brought forward from previous management measures, and it isn’t clear how well they have been implemented, especially given the ongoing increases in total catch of skipjack. The scientific committee recommends more comprehensive data collection relating to FADs.
Observer coverage on purse seiners is poor in areas not specified in the bridging measure and only 5% coverage is required on longliners greater than 20m in length. 20% is considered to be the minimum to be effective.
To help address IUU, the WCPFC maintains an IUU Vessel List, prohibits transhipments at sea between purse seiners (some exemptions apply) and requires all other transhipments to be documented and 100% observed as part of the regional observer programme.
In 2017 a Compliance Monitoring Scheme was introduced to assess and improve compliance with obligations, and penalise non-compliance.
Criterion score: Critical fail info
Approximately 19% of the WCPO yellowfin catch is taken in various, more subsistence style netting operations such as ring and gill nets (an increase from last year, when it was 15%). Gillnets used for catching tuna and tuna like species can be 7 km and are known for extremely high bycatch including endangered marine turtles, whales, dolphins and sharks. WCPFC bans the use of gillnets over 2.5km long, but monitoring is poor.
Based on method of production, fish type, and consumer rating: only fish rated 2 and below are included as an alternative in the list below. Click on a name to show the sustainable options available.Anchovy, anchovies
Herring or sild
Salmon, Atlantic (Farmed)
Salmon, Chum, Keta, Calico or Dog salmon
Salmon, Pink, Spring , humpback
Salmon, Sockeye , Red Salmon, Bluebacks, Redfish
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